Field of the Invention
The present invention relates to a cleaning device that removes residual matter such as toner on the surface of an image carrier with a cleaning member, and an image forming apparatus using such a cleaning device. Particularly, the cleaning device characteristically uses a cleaning member that includes a supporting member formed with a metallic plate spring and a contact member formed with an elastic material, the contact member being bonded to the supporting member with an adhesive. The contact member of this cleaning member is moved in the opposite direction of the moving direction of the image carrier, and is brought into contact with the surface of the image carrier, to remove residual matter on the surface of the image carrier. In this process, the contact member can be stably brought into contact with the surface of the image carrier by the supporting member with a sufficient contact pressure. Furthermore, the amount of residual matter staying on the end surface of the contact member brought into contact with the surface of the image carrier is prevented from varying in the longitudinal direction of the contact member, and the residual matter on the surface of the image carrier can be appropriately removed over a long period of time.
Description of the Related Art
In a conventional image forming apparatus, such as a copying machine, a printer, a facsimile machine, or a multifunctional machine having the functions of a copying machine, a printer, and a facsimile machine, a toner image is transferred from an image carrier moving while holding the toner image on the surface thereof, and residual matter such as toner remaining on the surface of the image carrier is then removed from the surface of the image carrier by a cleaning device. For example, after a toner image formed on a photosensitive member is transferred onto an intermediate transfer member such as an intermediate transfer belt or a recording sheet, residual matter such as toner remaining on the surface of the photosensitive member is removed by a cleaning device. Alternatively, after a toner image is transferred onto an intermediate transfer member, residual matter such toner remaining on the surface of the intermediate transfer member is removed by a cleaning device.
As such a cleaning device, a cleaning device 2 shown in FIG. 1A is widely used. In this cleaning device 2, the end of a cleaning member 3 formed with a plate-like cleaning blade made of an elastic material such as urethane is moved in the opposite direction from the moving direction of an image carrier 1 and is brought into contact with the surface of the image carrier 1 after a toner image is transferred, and residual matter t such as toner remaining on the surface of the image carrier 1 is removed from the surface of the image carrier 1 by the cleaning member 3.
In such a case where the end of the plate-like cleaning member 3 made of an elastic material is pressed against the surface of the image carrier 1, and residual matter t such as toner remaining on the surface of the image carrier 1 is removed, a certain amount of residual matter t is caught between the end of the cleaning member 3 and the image carrier 1, and the caught residual matter t functions as a lubricant to reduce the frictional resistance between the end of the cleaning member 3 and the image carrier 1.
However, if low-coverage image formation is continued for a long time, the amount of residual matter t caught between the end of the cleaning member 3 and the image carrier 1 decreases, or an environmental condition such as temperature or humidity changes. As a result, the frictional resistance between the end of the cleaning member 3 and the image carrier 1 increases. Due to the frictional force between the image carrier 1 and the end of the cleaning member 3, the end of the cleaning member 3 is pulled by the image carrier 1. In that case, the end of the cleaning member 3 is bent in the reverse direction, and ends up having a curled-up portion, as shown in FIG. 1B.
Consequently, the residual matter t such as toner remaining on the surface of the image carrier 1 cannot be appropriately removed by the cleaning member 3, or a load is applied to the image carrier 1, resulting in scratches on the surface of the image carrier 1 or incorrect movement of the image carrier 1.
JP 2002-268487 A discloses a cleaning member in which a contact member formed with an elastic material is bonded to the end of a supporting member with an adhesive in such a manner that the contact member protrudes from the end of the supporting member formed with a metallic plate spring. JP 2008-111972 A discloses a cleaning member in which a contact member formed with an elastic material is bonded to a portion located slightly away from the end of a supporting member with an adhesive so that the end of the supporting member formed with a metallic plate spring protrudes from the contact member, and the contact member of the cleaning member is moved in the opposite direction from the moving direction of the image carrier and is brought into contact with the surface of the image carrier, to remove residual matter such as toner remaining on the surface of the image carrier.
In a case where the cleaning member disclosed in JP 2002-268487 A is used, a contact member 3b formed with an elastic material is bonded to the end of a supporting member 3a with an adhesive 3c in such a manner that the contact member 3b protrudes from the end of the supporting member 3a formed with a metallic plate spring, as shown in FIG. 2. If the protruding portion of the contact member 3b protruding from the end of the supporting member 3a is too long in this process, the protruding portion is deformed over time, and it becomes difficult to bring the contact member 3b into contact with the surface of the image carrier 1 via the supporting member 3a. As a result, residual matter t such as toner remaining on the surface of the image carrier 1 cannot be appropriately removed. To prevent such a decrease in pressure, the pressure for bringing the contact member 3b into contact with the surface of the image carrier 1 is increased. In that case, due to the frictional force between the image carrier 1 and the end of the contact member 3b, the end of the contact member 3b is pulled by the moving image carrier 1 and ends up having a curled-up portion, as in the above described case with the plate-like cleaning member formed with an elastic material. As a result, the residual matter t such as toner remaining on the surface of the image carrier 1 cannot be appropriately removed, the surface of the image carrier 1 is scratched, or the image carrier 1 moves in an incorrect manner.
In a case where the cleaning member disclosed in JP 2008-111972 A is used, a contact member 3b formed with an elastic material is bonded to a portion located slightly away from the end of a supporting member 3a with an adhesive 3c so that the end of the supporting member 3a formed with a metallic plate spring protrudes from the contact member 3b, as shown in FIG. 3A. If the amount of the adhesive 3c for bonding the contact member 3b to the supporting member 3a is too large in this process, the adhesive 3c strays onto the end surface of the end of the contact member 3b, and the amount of the stray adhesive 3c varies in the longitudinal direction of the contact member 3b, as shown in FIG. 3B. Consequently, the amount of residual matter t caught between the end of the contact member 3b and the image carrier 1 varies in the longitudinal direction of the contact member 3b. As a result, the frictional resistance between the end of the contact member 3b and the image carrier 1 varies in the longitudinal direction of the contact member 3b. Due to this variation, the cleaning becomes inadequate, or the abrasion of the surface of the image carrier 1 becomes uneven, leading to density unevenness in a formed image, for example. Further, if the pressure for bringing the contact member 3b into contact with the surface of the image carrier 1 is increased in this case, the end of the contact member 3b is pulled by the moving image carrier 1 and ends up having a curled-up portion due to the frictional force between the image carrier 1 and the end of the contact member 3b, as in the above described case. As a result, the end of the supporting member 3a formed with a metallic plate spring collides with the surface of the image carrier 1, and the surface of the image carrier 1 is scratched, or the driving of the image carrier 1 is stopped, for example.
In a case where a contact member 3b formed with an elastic material is bonded to a supporting member 3a with an adhesive 3c in such a manner that the end of the supporting member 3a formed with a metallic plate spring is located in the same position as the end of the contact member 3b, if the amount of the adhesive 3c for bonding the contact member 3b to the supporting member 3a is too large, the adhesive 3c strays onto the end surface of the end of the contact member 3b, as shown in FIG. 4A, and the same problems as those in the case illustrated in FIGS. 3A and 3B are caused. If the amount of the adhesive 3c is reduced so that the adhesive 3c does not stray onto the end surface of the end of the contact member 3b, as shown in FIG. 4B, the end of the contact member 3b is pulled by the moving image carrier 1. As a result, the end of the contact member 3b not firmly bonded to the supporting member 3a is curled up, and the contact member 3b is detached from the supporting member 3a. 